Influence of water exposure on leakage of fillers and topography of composite resin restoratives.

Double-beam atomic absorption spectrophotometer was used to study the leakage of fillers from six brands of commercial composite resin restoratives, after 40 and 80 days of water immersion. In addition SEM was used to study the topographic changes of the immersed restoratives after the second test period. The results indicated that fillers as Si, B, Sr, Ba, Sb, Mg and Al leaked out in considerable amounts after the two immersion periods. SEM study revealed deteriorated picture of the restoratives characterised by fillers degradation, crack propagation and debonding. The authors believed that hydrolytic degradation of the fillers of composites was a great failure mechanism.